If there's a way to make motorcycles more complicated, manufacturers will find it. The latest thing is moveable aerodynamic flaps that either direct air over the rider or fold back to aid high-speed air penetration.

BMW Experimenting with Moveable Aerodynamics

With all the furor over the aerodynamic add-ons in MotoGP and how it is harming racing, you might think that manufacturers would avoid mentioning aero as much as possible. BMW obviously disagrees, however. The company is working on aerodynamic flaps that will either direct air away from the rider or fold back flush with the bodywork to reduce aerodynamic drag at speed.

BMW isn't the first manufacturer to do this: the new Moto Guzzi Mondello has a similar system of flaps mounted in the fairing. BMW itself has fitted moveable flaps to the K1600 series of bikes to direct air onto the rider.

Whereas the flaps on the Moto Guzzi are moved by electric servos, BMW's latest idea is to get rid of that complexity and weight and instead fit the flaps with soft springs. At slow speeds, the air passing over the flaps is not sufficient to compress the springs so the flap remains open, directing air away from the rider. Speed up and the air pressure on the flaps overcomes the springs and the flap swivels flush with the bodywork, decreasing air resistance.

A fairing can only be so big on a bike: looked at from the front, any number of Harley-Davidsons, Indians, and BMW RT tourers are getting on to be not much narrower than a small car. With the increasing use of wind tunnels, engineers can make the fairing as small as possible and use the flaps to 'tune' the airflow around or onto the rider.

The patent application drawings show three flaps fitted to the fairing, in high, medium, and low positions. As they use springs to keep them open, they can be tuned to close at different speeds, depending on how the engineers want the airflow to behave.

BMW is known to be developing new GS models and, while there is no guarantee that the new aero tech will find its way onto the new models, there is also the likelihood that the tech will form part of the keep-ahead-of-the-Joneses specification. Expect other manufacturers to jump on the bandwagon in due course.

Final Thoughts

It seems as if none of BMW's engineers have ever ridden in a truly hot climate, where you need more air passing over your body, not less. Riding a GS Adventure has been my lot for a number of years in South Africa and, let me tell you, the wind protection is almost too good, especially when riding in 30°C and higher temperatures. If you ever see pictures of a South African GS rider standing up while riding along a dead straight tar road, you now know why: it's in a desperate attempt to get some air to his overheating body.